A1 2013 AMI Cable where does it go to?

Hi

2013 A1 Petrol TFSI

I can't locate the AMI cable (with the yellow plug) which has disconnected from the rear of the (Concert) Radio unit (see attached image). I've had the glove box out, the centre console out and pulled my hair out! I've had my head in the driver's footwell and an endoscope as far as I can get it! I'm trying to trace it from source but can't find any suitable info to know where it might originate from in the car. Any ideas?

Back story: I 'upgraded' to Apple CarPlay using one of the units from eBay. Was plug 'n' play. Worked for a week and then, well, didn't. So, I had the radio out and noticed the lead had gone. Supplier is useless in terms of support. And when it works, it wasn't too bad, to be fair. If it wasn't for that pesky yellow plug!

Many thanks in advance

Steve